With the latest weekly reset, Bungie has introduced a new Exotic weapon quest to Destiny 2, but only for those who own the season pass for Season of the Undying (which is included with Shadowkeep). Acquiring the new bow, Leviathan's Breath, requires completing the Make Bows, Not War quest, which you can get started by speaking with Banshee-44 at the Tower. However, the first step involves tracking down the location of Banshee's hidden workshop. You won't receive a quest marker or much in the way of direction except a hint that Cayde can somehow help you.
You can watch the video above or follow our step-by-step guide to Banshee's workshop location. But as the Cayde hint suggests, you'll want to start out by going to the Tower's hangar; from there, you can go up into the catwalks and then through a series of rooms and hallways to get to the workshop and trigger the next step of the quest.